Identification and characterization of a novel fibril forming peptide in fungal starch binding domain.
Scanty information is available regarding the chemical basis for structural alterations of the carbohydrate-binding modules (CBMs). The N-terminal starch binding domain (SBD) of Rhizopus oryzae glucoamylase (GA) forms fibrils under thermal stress, presenting an unusual conformational change from immunoglobulin-like to beta-sheet-rich structure. Site-directed mutagenesis revealed that the C-terminal Lys of SBD played a crucial role in the fibril formation. The synthetic peptide (DNNNSANYQVSTSK) representing the C-terminal 14 amino acid residues of SBD was further demonstrated to act as a fibril-forming segment, in which terminal charges and an internal NNNxxNYQ motif were key fibril-forming determinants. The formation of fibril structure in a fungal SBD, caused by its chemical and biophysical requirements, was demonstrated for the first time.
Liu
Wei-Ting
WT
Institute of Molecular and Cellular Biology and Department of Life Sciences, National Tsing Hua University, No. 101, Section 2, Kuang Fu Road, Hsinchu 300, Taiwan, ROC.
Lin
Shu-Chuan
SC
Chou
Wei-I
WI
Liu
Tseng-Huang
TH
Pan
Rong-Long
RL
Tzou
Der-Lii
DL
Hua
Tzu-En
TE
Chang
Margaret Dah-Tsyr
MD
D000409:Alanine / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000682:Amyloid / Q000096:biosynthesis*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D005087:Glucan 1,4-alpha-Glucosidase / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D006358:Hot Temperature; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000235:genetics; D012233:Rhizopus / Q000201:enzymology*; D013213:Starch / Q000378:metabolism*
D000682:Amyloid; D005656:Fungal Proteins; D010455:Peptides; D013213:Starch; D005087:Glucan 1,4-alpha-Glucosidase; D000409:Alanine